<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>05流程控制</title>
</head>
<body>
<script>
    //1.顺序结构
    console.log(1);
    console.log(2);
    console.log(3);
    //2.分支结构
    let userName = 'Joker';
    if (!userName) {//若用户名为空字符串,转为布尔值false,!false为true,走分支1
        alert('用户名不能为空!')
    }else {
        alert('欢迎'+userName+'回来!')
    }
    //3.选择分支
    let gender = 3;
    switch (gender){
        case 1:
            console.log('先生');
            break;
        case 0:
            console.log('女士');
            break;
        default:
            console.log('保密');
    }
    //4.循环结构
    let names = ['张三','李四','王五','赵六','钱七'];
    for(let i = 0;i<names.length;i++){
        console.log(names[i]);
    }
    console.log('**********');
    console.log(i);
    //增强型for循环
    for (let n of names){
        console.log(names[n]);
    }

</script>
</body>
</html>